Driving in the snow with a Prius

In the US, 185/65R15 is the basic tire size. If your car has 16" wheels, you might consider buying 15" wheels and winter tires.

 

It's the ground clearance more than the tire size that limits the Prius in snow. You can't increase the overall wheel/tire diameter much to gain ground clearance as there isn't much room in the wheelwells.

I'm constantly plowing the side roads here in Edmonton. I should bill the city.

 

I use 15" steel wheels - standard Corolla issue I believe. I keep the stock rims & wheels for summer use.

One thing I regret - not getting winter tires with spikes right from the start.

The traction control is very sensitive, and there is too much torque/power when you take off from a stop/red light. Thus, one wheels slides if there is ice - common at stop signs - due to other cars w/o TC spinning their wheels.

If I hit such a patch of ice, I crawl forward for a whole second, it beeps, and people behind me wonder why I'm moving at 2km/hr.

Having spikes will make the TC much less prone to kicking in when it shouldn't. Norway winters are comparable to Quebec winters, and perhaps only adds 10$ per wheel.
You can't install them *later* it needs to be at purchase.

On cement roads will add to the noise level.

 

The next time there is 2-4 inches of snow on the ground, go to a large empty parking lot, and play around. Try putting the car into a skid. Do abrupt and gradual braking at various speeds, do abrupt turns, with and without braking, etc. In short, learn how the car feels in the snow and ice. You will kick in ABS, VSC, traction control at various times, and know how they feel, which will help driving in the future.

Inexperienced drivers can freak out the first time ABS brakes kick in and think they have no brakes. They will often do the wrong thing, make the situation worse, and cause and accident that the system was trying to prevent.

 

My post is going to be a little off-topic, but still closely related to the subject of this thread. We've been experiencing the toughest winter I can remember here in the Czech lately, so I had much more opportunities to test the snow handling qualities of my Prius than I ever expected .

I experienced problems with overly-cautious traction control many times and worked out some solutions I would like to share.

First rule is - do NOT rely on it, do NOT let it engage if possible. Be gentle on the accelerator.

Second - if you get stuck in snow, one wheel spinning slowly, other not moving at all, unable to move anywhere, try one of the following:

1) Rock the car forth and back by switching from D to R with your foot gently on the gas.

2) Stomp on the brake with your left foot. Put the car in "D". Stomp on the gas simultaneously (as if you were force-charging the battery). Once the ICE revs up a little, Release the brake instantly. This will cause the car to shoot forwards and would allow for much more wheelspin than usually for a moment, before the TC kicks in. This helped me many times to free the car from being stuck, unable to accelerate normally.

3) This is the last resort, but helped me several times after fruitless attempts to free the car by using steps one and two. Set the parking brake on. Turn the steering wheel fully to one side (left or right, depending on the direction you want to try to "sling" the nose of the car). Stomp on the brake with your left foot, select "R". Stomp on the gas while standing on the brake, release the brake instantly. This will most likely cause the nose of your car to slide to side (either to the left or right depending on the direction you put the steering wheel to), and may allow the wheels to grab on firm(er) ground if you are lucky.

I never tried to disable TC by putting the car into the "inspection mode", because I didn't want to risk blowing my transaxle. However, it might be the very last resort to try out if you are in real trouble and if you think that allowing wheelspin would help you. But I do NOT reccomend it myself, as I never tried this.